Sweet onion and cauliflower tart

Method

1. For the pastry, pulse together the flour, thyme, a pinch of salt and the chilled butter in a food processor to make large crumbs. Sprinkle over 3 tbsp cold water and pulse again to bring the mix together to make a dough – use another tbsp water if it’s a bit dry. (Alternatively you can do this by hand in a mixing bowl – use your fingertips to rub in the butter, then use a dinner knife to mix in the water.) Tip out onto a sheet of cling film, shape into a ball, then wrap the pastry in the cling film and flatten it with your palms to make a disc. Chill the pastry in the fridge for 30 minutes.
2. Heat a glug of oil in a large frying pan and fry the onion over a low-medium heat for 20 minutes until softened and slightly caramelised. Add a pinch of salt and the sugar and cook for another 5 minutes. Set aside. 3 Meanwhile, in another frying pan (with a lid), heat the butter and fry the cauliflower florets for 5 minutes, turning, until golden. Transfer half to a plate and set aside, then add the bay leaf and milk to the pan and simmer with the lid on for 10 minutes or until tender. Scoop out the cauliflower (discard the bay) and whizz in a food processor with just enough of the cooking liquid to make a purée (or do this in a bowl with a stick blender). Discard the remaining liquid. Pour the pureé into a large jug or bowl and leave to cool.
3. Heat the oven to 200°C/180°C fan/gas 6. Roll out the chilled pastry on a lightly floured work surface to roughly the thickness of a £1 coin. Carefully use your rolling pin to lift the pastry and unroll it over the tin. Line the base and sides of the tart tin with the pastry, pressing it into the edges and flutes. Trim any excess with a sharp knife, leaving a small overhang. Prick the base a few times with a fork, line the case with foil, then fill with baking beans or uncooked rice. Chill for another 10 minutes.
4. Bake the tart case for 20 minutes, then remove the foil and baking beans/rice and return to the oven for 6-8 minutes until the pastry is golden and feels sandy to the touch. Take the tart case out of the oven and turn the temperature down to 170°C/150°C fan/gas 3½.
5. Spoon the cooked onions over the base of the tart and scatter over half the grated cheese (see Know-how), the black olives, the reserved cauliflower florets and the thyme leaves. Beat the eggs and cream into the cooled cauliflower purée, season with black pepper, then put the tart case on a baking sheet on an oven shelf and pour in the egg mixture. Scatter over the remaining cheese and bake for 30 minutes until golden and the filling has set. Serve warm.